I feel like I made a mistake

I’ve been single for about 4 months. I got on tinder about a week ago and me and this guy matched and we clicked and we both seemed to be really into it. We had been talking for a few days and we met up at his place. And a little while later we had sex. Ever since then we don’t talk much anymore. I cant help but feel like I made a mistake by having sex with him and now we don’t talk much like we used to. I’m not sure how to really feel because I’ve never had sex with someone within a few days of knowing someone. It’s weird and different for me and I’m not sure how to feel or what to do